EMALS (Electro Magnetic Aircraft Launching System) – The Future Technology Part 1

Launching a new triweekly series " The Future Technology Series " . In the first part i will take you through an basic overview and operational details of the modern catapult system of the giant aircraft carriers.

 EMALS (Electro Magnetic Aircraft Launching System) – The Future Technology

INTRODUCTION-

As we all know an aircraft carrier holds a matter of prime importance for a navy. The aircraft carriers serves as the military base of a nation, they are used to project power in remote land, where it is really a difficult task to set up a land based military base. Only a few of the nations can afford and maintain such giant ships. They house several number of aircrafts and personals who works 24*7 round the year to protect the world against hostile forces. U.S.A, U.K., Brazil, India, France, Russia, Japan, China, Spain and a few other’s navies only have such lethal vessels.

USS Nimitz (world’s largest aircraft carrier) size comparison

(Courtsey: www.wikipedia.org)

 Today the U.S.A has a total of 19 aircraft carriers, out of which 10 are supercarriers, they have more than 100,000 tons of displacement and 9 are amphibious assault vessels which are small compared to the supercarriers and used to launch only helicopters and VTOL aircrafts.

Now when the carriers have to launch an aircraft the procedure is not simple as it involves in launching an aircraft from land based runaway, where the aircraft taxi to run away and simply increases its thrust and take off. In case of the aircraft carriers it’s really a complex process with use of steam catapults (Used by the U.S.A., France and Brazil). The use of catapult gives these navies an edge over the other navies because they can launch the aircraft with greater payloads which includes more armament and fuel which is a necessity in combat and recon operations. The basic physics tells us that to produce lift the aircraft carrier can sail towards the direction of wind and more is the airflow over the wing the less is the minimum take off speed for the aircraft. But practically every time it’s not possible and feasible. Day by day the increased payload involving in naval aircraft operations can’t be done without the help of a simple device i.e. CATAPULT.

THE CATAPULT-

The catapult is a device installed in the flight deck and is attached to gear (forward) of the aircraft to be launched consisting of a piston attached to a cylinder (which is really very large). To propel the catapult several methods can be used. During early 20^th century when first aircraft carriers came they operated with the help of spring catapults. They were not really successful but fortunately man found a way to launch aircrafts from the ships for the first time. But as soon as the world war came the Research and Development towards improving and modernising took place, years of hard work and advancement of technologically resulted in the development of steam catapults.

Structure and working of steam catapult in aircraft carrier

(Courtsey: www.googleimages.com)

The basic principle of steam catapult is that the catapult is attached to the nose gear of the aircraft to be launched, the catapult being connected to the pistol which is further connected to the cylinder. There are 2 cylinders which are charged with steam and the piston is in compressed position. It is really very complex and time consuming process to charge the cylinders to appropriate level of required steam pressure. The aircrafts engines also run to  along with catapults and produces thrust. Behind the aircraft the jet blast deflector also known as blast fence is raised up with the help of hydraulics and they act as a safety device which redirects high energy coming from exhausts of the aircraft and thus saves from potential injury and damage to other structure and installations on board. The crew checks up if everything is right and the aircraft is ready to launch, the catapult officer who is responsible with all these tasks then releases the pistons, which were previously in holdback position. After they were released a very large amount of force now drives the aircraft along with the help of thrust produced by the aircraft itself and the aircraft finally takes off.

Position of catapult in an aircraft carrier

(Courtsey: www.quora.com)

But operating the steam catapult involves lot of fresh water which is obtained by desalination of sea water. Lot of maintenance is also required to keep them operating even during adverse conditions to keep them operating. Not only this they significantly affect the cost during construction and maintenance. Significant time is also required to recharge them with steam. One of major adversary faced by the aircrafts are lot of stress in its airframe, the solution to all these problem is solved by the development of the “EMALS System”

The Revolutionary Solution -EMALS System

But with the changing time and the development it was felt to replace the catapult with the EMALS system. Years of research by the U.S.A. and developed by the American company “General Atomics” the EMALS system is now ready to be launched along with the new generation of lethal aircraft carriers USS Gerald R. Ford, which will replace the USS Enterprise after 51 years of her decorated service. This aircraft carrier unlike the conventional aircraft carriers is equipped with EMALS or Electro Magnetic Aircraft Launching System. The EMALS system launches the aircraft using a linear motor drive rather than the conventional Steam Catapult piston-cylinder drive.

Computer Generated 3-D structure of linear induction motor in EMALS

(Courtsey: www.wikipedia.org)

WORKING OF EMALS System-

The electromagnetic aircraft launching system consists of the catapult attached to a very high electrically driven linear induction motor. The induction motor is made of two 300-foot-long stationary beams, or stators, spaced a couple of inches apart and a 20-foot-long carriage, that is sandwiched between the two beams and can slide back and forth along their lengths.

The beams are made up of lot of segment . Along the spaces of the beams there lies the wiring which helps to run the whole system and is one of the prominent component of EMALS. The computer system programmed onboard the vessel selectively switches on the segments of the beam which generates an electromagnetic force along the carriage (catapult) . Thus Magnetic effect is the principle of operation for this system.

The aircraft launching takes place in the same manner as in the steam catapult after that. Only the difference is that 0 amount of steam is used and all is magnetically driven modern generation system.

EMALS system in the USS GERALD R. FORD

(Courtsey: USA Department Of Defence)

Advantages of EMALS System

Research studies shows that the EMALS system is much better and efficient due to the following reasons, which are as follows-

1.       EMALS system are much more lighter compared to the steam catapult systems, this helps the aircraft carrier to be loaded with other important stuffs required during its sailing period.

2.       As it occupies less space also this will help in creating room for the serving personals and aircrafts stationed in the carrier.

3.       Studies shown that they have 5% more operating efficiency compared to the steam catapult systems and delivers can supply with 121 mega joules of force which is 29% more than the older steam catapult’s 95 mega joules of force only.

4.       Less manpower, maintenance is required to operate the EMALS.

5.        The future ships planned by the US, Indian and Chinese navy will be equipped with this technology and thus will be more electrical ships rather than the current ones, as the EMALS system requires a large amount of electric power to operate. Overall it will improve the ship, because the replacement of the steam catapults will help to free a significant space and will create room for energy efficient vessels.

6.       They will prove to very helpful to launch the future aircrafts which are heavier compared to current ones and will be having more payload compared to the current ones.

7.       An electromagnetic catapult can launch an aircraft every 45 seconds.

Testing of the EMALS system using a dummy model for the first time

(Courtsey: US Depatment Of Defence)

No doubt the EMALS systems uses a huge amount of power, to solve this problem the ships will be fitted with high powered rotors, during the operation the system will draw power from the stored systems and the generators too, thus the dual system power supply will help it. There will be large power drop on board the ship but the during the interval of 42 seconds of launching another aircraft , there will be complete recovery of power.

Thanks

Ayonavo Biswas

                                                                                                                                        

  

Understand The Basic Parts Of The Ship- Part 1

As we all know a ship is a very large body. Being such a large object ,it's really important to have some uniformity in naming it. Whenever you see a ship in sea you just know it's a ship. But this post will update your knowledge. Always remember one thing that sharing the knowledge will help all of us to grow.
While refering the left and right side of any marine vessel we use the terms ie Portside and Starboard side . The Port side refers to the left side of the vessel when we are facing towards its bow (ie its forward) , whereas the Starboard side refers to the right side of the vessel when we are facing towards its bow. The direction in which the vessel move in forward direction is known as its bow(also known as stem ) whereas the rear side of the vessel is known as stern(also known as astern,aft ). I will provide you with a simple picture to remember this stuff.

(Courtsey:https://aceboater.com)

(Courtsey:http://www.boatsafe.com)

Compared to the ships of older times currently ships are literally very large in size,have very less crew infact research is going on to produce unmanned ships which will be self-driven with the help of Artificial Intelligence process is also going on. During the starting of World War the speed is the thing which matered a lot but now the efficieny of  the vessel which is playing a significant role. 

RINA (Royal Institute of Naval Architect ) is an independent regulatory body which makes several rules , regulations regarding construction,operation,safety and maintaince in the field of naval architecture. There are several members starting from students to working and research professionals who are working hard day by day and attached with RINA to reform this diverse field. 

But while the construction of ships it's important that the shipyard which is responsible for its construction maintain all the rules and regulations and for these the Classification Societies are responsible. Starting from regulation of construction of ship they are responsible to check all the detailed stuff so that the ships are fit for the purpose. We can take a simple example suppose we have to design a vessel and the steel plate required is of 7mm , but due to inavailability of the 7mm plate the shipyard uses 5mm or 9mm plates , this will surely affect the performance of the ship to a large extent , it may also lead to sinking of the vessel .

The history of classification societies dates back to the late 18th century when several merchant ships used to be loaded with extra goods (overloaded) and it resulted in the sinking and capsizing if the vessels. But one the oldest classfication society that is Lloyd's Register came who monitored the construction of vessels and made a rule to load the vessels upto a certain level and thus assigned class to it . "The class A1" shows the ships construction is best in terms of quality of machinary to every manufacturing process.Several classification societies are avialable which are established to deal with the following stuffs like DNV-GL,Lloyd's Register of Shipping, Nippon Kaiji Kyokai, Bureau Veritas ,Indian Registarar Of Shipping,American Bureau Of Shipping, Korean Registarar Of Shipping and many more.

IACS( International Association Of Classification Society ) was established during 1968 by the 7 classification societies , headquatered in London(U.K) , now have 12 members is one of the most technogically sounded association of classification societies.They meet during several occasions to discuss and develop new rules and regulations and share the knowledge for the benifit of industry.

Now whenever you see any vessel let it be boat, steamer, cruise ships or cargo ship , you are assumed to see it. You may say its so big , but when someone asks you what's so big ? You may say its the body of the ship . The thing which you refers as body of the ships which involves several structures installed is known as the Hull of the Vessel. It can be defined as 3 dimensional structure made to accomodate and carry goods and man inside it , installed with several structures and machinary inside and outside of it, it faces all the external and internal forces and move through the water.

Ok is it complex , no problem , when you say the body of ship , simply in technical terms its called as Hull.

Hull of the ship 

(Courtsey: www.http://cdn.jotun.com)

Hull Generated and representation of Hull in 3D manner

(Courtsey:http://cadcamcae.eafit.edu.co)

In olden days the naval architects also known as ship designer use to design the ships by drawing the structure of hull in paper and calculations are done using the use of simple calculators and scale . But now due to introduction of computers several softwares came , one of the basic software is Autodesk's AUTOCAD , which can help to form the structure of hull and other parts. Specialised softwares like DELFT Ship , CATIA by Dassault , Napa , etc are used by naval architect. Relying on technogically not only make the work easier but also creative and interesting .

The construction of hull of the ship starts with the drawing of lines plan of ship. Well lines plan is one of the most proper way to define the hull form of any vessel and is the basic necessity. 

Lines Plan of a ship 

(Courtsey:http://www.fao.org)

The lines plan of the ship consists of 3 different plans with the help of which we represents its 3-D structure. Hence 3 plans are being made, in simple words during construction of a building we make its top, side and front view in a similar manner lines plan consists of Profile,Body Plan and Half Breadth plan . 

Lines Plan of a ship representing its hull form consisting of : Body Plan, Profile and Halfbreadth plan (also known as wateline)respectively from top to bottom 

(Courtsey:http://www.purgit.com)

These 3 orthoganal planes mutual intersection forms the 3-D structure of hull of any vessel.

As we are saying about all these lines plans now finally i would like to end this post by showing you the 3 different planes of the ship which are known as follows:

1. Middle Line Plane( Longitudinal Plane)

2.Transverse Plane

3.Waterplane

Planes of the Ship or any marine vessel

(Courtsey: Basic Ship Theory )

Thank you very much for reading the post , i will be really thankful if you got to knew new stuffs about the ship . Please share the page among all , and help to share knowledge.

Thank You 

Ayonavo Biswas

Why Ships are so Important

Why Ships Are So Important?

A cruise ship: Majesty Of The Seas

(courtsey: www.alphacoders.com)

Everyday the world is growing, the growth is being judged by the capital, investments , technology, manpower , resources. In a competitive world of today none of the nation can expect self sufficieny at all the levels. Even the developed nations need the help of the developing nations to grow. But have you ever thought what helped in that growth ?

Well its trade , yes trade and business not only helped in growth but also resulted in conquering nations to establishment of new colonies during post 15th centuries by european nations. Also the mighty egyptian, harappan , greek, chinese and many other civilizations flourished and traded various products among each other.

Now this trade is being carried out by the people with the help of land and sea routes. But a dramatic event occured on 20th May 1498 when one of the most famous route was discovered by the great portuguese sailor Vasco Da Gama. Well due to this the history of the world was changed for forever . Within a century the British East India Company established their trade in India, downfall of lot of empires took place , the mughals , sikhs , kingdom of bengal , kingdom of mysore  and many other felt helpless. The great mutiny of 1857 was also one of the prominent event.

Route followed by Vasco Da Gama 

(Courtsey: www.photobucket.com )

But trade was also between India and Europe before the 15th century, the silk route is a famous example of this , so what happened ? 

The large instability and domination by the european empires came only after the discovery of sea routes and good ships . 

YES SHIPS not only helped them to come over a new continent but also to sustain for centuries. During 326 B.C. Alexander the great tried to invade India ,but unfortunately he couldn't do it. Capturing India was the only way to sustain , the land tranport system was not developed to transport goods in large volume, it's a really difficult task even today to do that.
So the ships and marine routes were the best possible routes to not only invade the whole subcontinent but also it will be key to infinite resource for centuries.
Even today the crisis in South China Sea between China and rest of the world is dominated by the navies , different types of ships patrolling and keeping watch & carrying operations. Not only this the western nations this time is giving thrust to air-strikes to eliminate ISIS and other terrorist organisation, the Aircraft Carriers acts as a floating airbase and help to eliminate the threat in any part of the world.
Well now we have discussed a lot about war , now lets come to peaceful applications of ships.
More than 90% of the world's trade is being carried out by the ship today. Starting from your mobile phone you to the candy you are eating is being manufactured in a country and then shipped to whole world. This shipment is carried out by the NYK, Maersk, APL, COSCO and many other companies. Today the world is connected by trade. Ships are the most important resource without which the world economy will be handicap.
Moreover today ferries are also an important resource to promote tourism and also helps the people to move people from one part to another .
In next post we will see some more & new exciting facts about ships.
Thank You
Ayonavo Biswas